"There are hints that this year is one where more birds took a break from laying but were still present at the breeding sites."
This was called "loafing" by scientists and the birds were labelled "floaters" as they wandered around the colony or stand on empty nests.
"Those on an egg sit very snugly and firmly on them so can be recognised as breeders."
Wells said weather had made it a challenging mission for the team, "but a window in the westerlies arrived, the photographic data collected and all of the team were flew home safely".
"The survey gives us valuable data on breeding patterns and adult populations," Wells said.
This is the ninth time the annual survey has been carried out.
The sea lion survey has been carried out since 1996 and in 2016 it was estimated there were 1727 pups on the island, a 15 percent increase on the lowest estimate from 2009.
The New Zealand sea lion study is funded by the DoC Conservation Services programme.